Hi Mark!
Generally I work around this using hidden notes or notes with hidden stems. In
your example I think you want a tie rather than a slur (since it’s a held
note), but they both work in the same way with regard to voices.
In your example it could look like:
\version "2.22"
lowerA = \new
Hi.
I have a score that, in the piano, has a slur crossing voices (in the
example the slur would end up with the B being held for a 4 count).
There is a note in the LP manual saying that slurs must all stay in the
same voice, so is there a work-around for this kind of thing?
Many thanks!
.