Actually, that is an important question because immigration is clearly being relied upon to make more and more of a contribution to francophone communities outside Quebec. The main problem is that many of those immigrants do not have French as their mother tongue. So, they do not necessarily meet the conditions of paragraph 23(1)(a). As they were not necessarily educated in French in a primary school in Canada, they are not eligible under paragraph 23(1)(b). That said, I know that a lot of schools still take in those children of immigrants.
On February 14th, 2017. See this statement in context.