Since this site is now in beta, it is time to have these conversations with the folks who are actually building this site. Please bring your comments and discussions to this site's 'meta' support forum so not to split these conversations. Thanks.
Elisp questions are always relevant to Emacs, e.g. It is hard to ask an elisp question that is not related to Emacs. I think they should be explicitly on-topic on emacs.SX, and new elisp questions on stackoverflow should be migrated over to emacs.SX.
ELisp questions are a subset of Emacs questions. All ELisp questions can be treated as Emacs questions by the fact that ELisp is used pretty much exclusively within Emacs. Thus, I think it is implicit that an ELisp question is on-topic on emacs.SX and the name doesn't need to make it explicit.
You need to be careful here. If this post is representative: What to expect in the Emacs private beta, then questions that are too programmy are supposed to stay on SO. Which I take to mean that outright Elisp programming questions would be considered by some as explicitly off-topic.
I think this is silly, but it reflects the inconsistent/irrational way Emacs questions have been treated on the Stack Exchange network.