It's not the tuning that makes the difference between a banjo and a banjolele, it's the size of the instrument, and the type of strings used. Banjoleles have a much shorter length of string, and typically use gut (or these days nylon) strings.

The actual tunings can vary according to taste in both cases, though Will is of course correct about the most customary ones. (I've started a thread just now about an odd ukulele tuning I rather like.)

I think the term banjo-ukulele is preferable to banjolele really, because the sound as the way they are generally played is much more akin to ukuleles than to banjos.