I've heard from some people that one can't "choose" to dream about Elyahu HaNavi and that whenever one dreams about him it's **for sure** the **true** Eliyahu HaNavi, meaning, it was the prophet himself showing up in the dream, with a message or something.

Now, *if the above is true*, then whatever Eliyahu says in the dream must necessarily be true, otherwise he would be spreading lies around, no?

So, is the above true? Is there a source for that?