I've been doing some tests with the frost and fire versions of it, and can't decide how it works, too many numbers in the screen. If an enemy is hit by the orb and then the orb explodes, will it be hit twice? First time when the orb hits it and the second time when the explosion hits? Or once the orb hits an enemy, the explosion will have no effect on it?
i've been using the Flame Orb for quite a while now and I'm pretty sure it hits twice with the explosion.
I run on Hard difficulty to find new legendaries and so far, I never oneshoted anything with the trail itself (they can die after 2-3 sec but not instantly) however when they're hit by the explosion they are OS.
My thought is, when the orb travel it only applies the trail effect and then explode at the end. So a monster being too close from you will only be affected by the trail.
The Forst Orb instead doesn't seem to have a real "explosion" effect. It's just a "path damage". It only hit once. The explosion is just for more "coolness" imo. I didn't notice doing more damage when the Frozen Orb hit at the edge (path + boom). it always seems to be the same.
As for the lightning, I didn't really test it so I can't say ^^
I've done some tests, and I would say both the frost and the fire orb will hit twice if they hit an enemy and then explode in their range. I haven't tested the electric orb yet, but I would say it will be the same. Not sure about the arcane versions of it.