Hi and welcome in!!!
All members of the same evolutionary line have their own moves and both fast and charged moves ‘reroll’ whenever you evolve anything. What it can reroll to is entirely dependent upon the evolution’s movepool and unless special events are in play, you won’t acquire any elite moves, even if it’s an elite move on the prior form.
The only time anything will evolve to an elite move will be during specific events, although as Lick on Gengar was a raid day exclusive move, as I recall, it may not be in the usual rounds of event rotations.
Depending on why you want it, Shadow Claw is just as good in PvE and generally seems to be preferred by everyone in PvP.
That said, if you really want a Lick Gengar, EFTM’s are comparatively plentiful so go for it once you evolve.