Maíz is the actual plant and the grains that come from such plant.
Elote is the cob.
So really, in english you would say, let's eat a corn on the cob, whereas in spanish, you would say, vamos a comer un elote.
Do you want corn in your burrito? Quieres maíz en tu burrito?
You wouldn't say, do you want corn on the cob in your burrito, correct?
Same in spanish. You would't say, Quieres un elote en tu burrito? Hope that helps.
Sorry for the double post, didn't see i posted as a comment.