Lightning Overload

I found a fool proof way to SOLO this in 7.1.5 with any class. It's easy as it gets.

Put the boss in the SE corner of the room where the door to the next area is and face him to the statue in the corner. Now just stand there. Jin'rokh will spawn his orbs in the corner and they will get stuck there. All you have to do is wait for him to spawn two orbs on top of each other and boom you are done.

Here is a screenshot http://imgur.com/a/DYAov . Good Luck!

Edit- still works 7.2.5 - I added some more screenshots and some more details to the album. The key to getting this to work is making sure the boss is basically touching the wall of the waterfall area. You want him in there as far as you can get him. I run into the very corner of the room and then come back out to get right under the boss.

Added a video: https://youtu.be/z7V_hAbQDPU still working in 8.3

An extremely easy and painless way to get this achievement is to have the members of your party with a Traveler's Tundra Mammoth (or similar 3 person mount) mount up, and have as many of your dps as possible mount up with them as passengers. Simply ride in a circle around the room and wait until two of the three riders of any mammoth are targeted with orbs. Shortly afterwards, the orbs will line up as they follow the riders and touch each other and the achievement will trigger. You do not need to kill Jin'rokh for the achievement.

This almost definitely isn't intended behavior, but we accidentally got this achievement without needing to kite an orb. If the player targeted by the orb dies shortly after the orb spawns, the orb stays on its spawn point until the next one spawns, at which point both orbs collide.

Also, confirming that you get this achievement the moment the orbs collide; you don't have to defeat the boss afterwards.