Shaman level 20 talent, Strikes Twice:
When you lightning orb crits it instantly respawns on your totem.
Have not seen this mentioned officially anywhere, but have heard it mentioned by several people.
It has been said that it will continue to check for crit and respawn lightnings accordingly until the normal lightning orb hits the target, then it stops checking for crit and respawning until the next normal lightning orb spawns. The more time the lightning orb spends traveling in the air, the longer your window of opportunity to respawn due to crits…is it true that these two are connected?