Welcome to Dreamviews,

I dont smoke it myself so can't give you any first hand experience. I believe we do have quite a few members who both smoke cannabis and lucid dream, so this would seem to suggest its not a huge problem.
Im leaning towards shockwaves advice though, from my understanding cannabis has a negative effect on memory, which in theory could hinder both recall and the ability to spot anomalies in dreams that could be considered dream signs (eg realising that a minute ago you were in your house and now you're at the beach etc). It maybe worth giving it up for a few months while you initially get into LDing. You could always do an experiment at a later date to test how much it affects your LDing

Good Luck.

RooJ