simply create a “Song–>OnLoad” binding in every song file that sends a program change to the MIDI port of your lyrics tablet. But that means you have to create this in every song.
Use a binding in your background rack: Source: Set List->selected program" Target: Tablet MIDI port, program change - maybe you’ll need “program change (banked)”. This will work without touching every song, but you’ll need to have your master set loaded as a setlist; without a setlist, this binding will not do anything…