That would appear to be the case, as their continued presence is commonly ignored.
The point, however, would be more along the lines of: if Jews convert to Islam, do they cease to be Jews? (Interestingly, both Christianity and Islam claim to worship the same biblical God; they both claim Judaism as their religious ancestor.)
Well, technically, that makes no sense. The question was about Lebanon belonging to Israel, not where Jews and Arabs claim descent from on religious grounds.