lgtm, modulo some more formatting nitpicking. If you fix the formatting
and mail me the patch, I'll push it.

Here it is. --
Boris Shingarov
Work on Lilypond under grant from Sonus Paradisi / Jiri Zurek (Prague),
Czech Science Foundation, Project No. 401/09/0419
diff --git a/lily/constrained-breaking.cc b/lily/constrained-breaking.cc
index 2fead24..31d2cf0 100644
--- a/lily/constrained-breaking.cc
+++ b/lily/constrained-breaking.cc
@@ -525,4 +525,8 @@ Line_details::Line_details (Prob *pb, Output_def *paper)
   title_ = to_boolean (pb->get_property ("is-title"));
   compressed_lines_count_ = 1;
   compressed_nontitle_lines_count_ = title_ ? 0 : 1;
+  SCM last_scm  = pb->get_property ("last-markup-line");
+  last_markup_line_  = to_boolean (last_scm);
+  SCM first_scm = pb->get_property ("first-markup-line");
+  first_markup_line_ = to_boolean (first_scm);
 }
diff --git a/lily/include/constrained-breaking.hh b/lily/include/constrained-breaking.hh
index bb8a1d0..f36ab74 100644
--- a/lily/include/constrained-breaking.hh
+++ b/lily/include/constrained-breaking.hh
@@ -52,6 +52,8 @@ struct Line_details {
      class. */
   int compressed_lines_count_;
   int compressed_nontitle_lines_count_;
+  bool last_markup_line_;
+  bool first_markup_line_;
 
   Line_details ()
   {
@@ -71,6 +73,8 @@ struct Line_details {
     title_ = false;
     compressed_lines_count_ = 1;
     compressed_nontitle_lines_count_ = 1;
+    last_markup_line_ = false;
+    first_markup_line_ = false;
   }
 
   Line_details (Prob *pb, Output_def *paper);
diff --git a/lily/include/page-breaking.hh b/lily/include/page-breaking.hh
index 2e5283d..d497d49 100644
--- a/lily/include/page-breaking.hh
+++ b/lily/include/page-breaking.hh
@@ -127,6 +127,7 @@ public:
   bool too_few_lines (int line_count) const;
   Real min_whitespace_at_top_of_page (Line_details const&) const;
   Real min_whitespace_at_bottom_of_page (Line_details const&) const;
+  int orphan_penalty () const;
 
 protected:
   Paper_book *book_;
@@ -179,6 +180,7 @@ private:
   int max_systems_per_page_;
   int min_systems_per_page_;
   vsize system_count_;
+  int orphan_penalty_;
 
   vector<Line_division> current_configurations_;
   vector<Break_position> current_chunks_;
diff --git a/lily/page-breaking.cc b/lily/page-breaking.cc
index e0a08c0..dc71659 100644
--- a/lily/page-breaking.cc
+++ b/lily/page-breaking.cc
@@ -174,6 +174,7 @@ Page_breaking::Page_breaking (Paper_book *pb, Break_predicate is_break)
   systems_per_page_ = max (0, robust_scm2int (pb->paper_->c_variable ("systems-per-page"), 0));
   max_systems_per_page_ = max (0, robust_scm2int (pb->paper_->c_variable ("max-systems-per-page"), 0));
   min_systems_per_page_ = max (0, robust_scm2int (pb->paper_->c_variable ("min-systems-per-page"), 0));
+  orphan_penalty_ = robust_scm2int (pb->paper_->c_variable ("orphan-penalty"), 100000);
 
   if (systems_per_page_ && (max_systems_per_page_ || min_systems_per_page_))
     {
@@ -1415,3 +1416,9 @@ Page_breaking::min_whitespace_at_bottom_of_page (Line_details const &line) const
   // FIXME: take into account the height of the footer
   return max (0.0, max (padding, min_distance + line.extent_[DOWN]));
 }
+
+int
+Page_breaking::orphan_penalty () const
+{
+  return orphan_penalty_;
+}
diff --git a/lily/page-spacing.cc b/lily/page-spacing.cc
index 8919257..8dbf183 100644
--- a/lily/page-spacing.cc
+++ b/lily/page-spacing.cc
@@ -245,6 +245,18 @@ Page_spacer::calc_subproblem (vsize page, vsize line)
 	    penalty += lines_[page_start-1].page_penalty_
 	      + (page % 2 == 0) ? lines_[page_start-1].turn_penalty_ : 0;
 
+	  /* Deal with widow/orphan lines */
+	  /* Last line of paragraph is first line on the new page */
+	  if ((page_start > 0) &&
+	      (page_start < lines_.size ()) &&
+	      (lines_[page_start].last_markup_line_))
+		  penalty += breaker_->orphan_penalty ();
+	  /* First line of paragraph is last line on the previous page */
+	  if ((page_start > 0) &&
+	      (page_start < lines_.size ()) &&
+	      (lines_[page_start-1].first_markup_line_))
+		  penalty += breaker_->orphan_penalty ();
+
 	  demerits += penalty;
 	  if (demerits < cur.demerits_ || page_start == line)
 	    {
diff --git a/lily/paper-book.cc b/lily/paper-book.cc
index 79896e6..f1ee2ec 100644
--- a/lily/paper-book.cc
+++ b/lily/paper-book.cc
@@ -516,15 +516,20 @@ Paper_book::get_system_specs ()
 				  paper_->self_scm (),
 				  page_properties,
 				  scm_car (s));
-	  for (SCM list = texts ; scm_is_pair (list) ; list = scm_cdr (list))
+	  Prob *ps;
+	  SCM list;
+	  for (list = texts ; scm_is_pair (list) ; list = scm_cdr (list))
 	    {
 	      SCM t = scm_car (list);
 	      // TODO: init props
-	      Prob *ps = make_paper_system (SCM_EOL);
+	      ps = make_paper_system (SCM_EOL);
 	      ps->set_property ("page-break-permission",
 				ly_symbol2scm ("allow"));
 	      ps->set_property ("page-turn-permission",
 				ly_symbol2scm ("allow"));
+	      ps->set_property ("last-markup-line",  SCM_BOOL_F);
+	      ps->set_property ("first-markup-line",
+	    		  list == texts? SCM_BOOL_T : SCM_BOOL_F);
 
 	      paper_system_set_stencil (ps, *unsmob_stencil (t));
 	      ps->set_property ("is-title", SCM_BOOL_T);
@@ -544,6 +549,18 @@ Paper_book::get_system_specs ()
 	      // FIXME: figure out penalty. 
 	      //set_system_penalty (ps, scores_[i].header_);
 	    }
+         // We may want to place a check here, for whether the line is too short
+         if (list == texts)
+           {
+             // if there is only one line in the paragraph,
+             // do not try to avoid orphans
+             ps->set_property ("last-markup-line", SCM_BOOL_F);
+             ps->set_property ("first-markup-line", SCM_BOOL_F);
+           }
+	  else
+           {
+             ps->set_property ("last-markup-line", SCM_BOOL_T);
+	    }
 	}
       else
 	assert (0);
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