I am looking for an analysis or explanation of the phrase "if you have questions, then I'll be available after class." Although this is structured like a conditional, it's not actually a semantically reasonable conditional statement. Instead of using the first clause to limit the scope of the truth of the second clause, the speaker is using the first clause to address the second clause to a subset of the audience. I've come across people using phrases structured like this frequently in casual conversation in the United States.
This doesn't seem to work with any of the definitions of "if" or "if... then... " found in OED Online, dictionary.com, or Collins.
