Ulrike Fischer wrote:
You use harf mode, and so you should use luahbtex not luatex.
Thank you Ulrike — David C. made this very point yesterday, after which all worked as hoped. Having switched to LuaHbTeX for this project, I now have a new problem however — LuaHbTeX does not form ligatures for (e.g.,) Adobe Caslon Pro or Garamond while it does so for Adobe Minion Pro. Question raised on LuaTeX list.
-- /Philip Taylor/