Why not use text marks, http://lilypond.org/doc/v2.25/Documentation/notation/text-marks ? They are intended exactly for textual indications that should appear at the top of each system, i.e. above the lyrics in your case.
Because I wasn't aware of their existence :)
They work just nicely ... and I really need to make a habit out of carefully reading the "what's new" documentation of new versions...
Thank you for pointing me to it, Michael -- Michael Gerdau email: m...@qata.de GPG-keys available on request or at public keyserver