Out of curiosity, what are you defining as the "Lightning Stun"?
Are you referring to Electrocute, a 1 minute (or 50 seconds if spec'd into Oppressing Force) cooldown stun that does use lightning for it's animation and last for 4 seconds.
Whirlwind, which is another 1 minute (or 45 seconds if spec'd into Suppression) cooldown stun, that could possibly affect multiple targets if spec'd into Oppressing Force, and lasts for a total of 1 minute.
Jolt, which is an interrupt ability that lasts for 4 seconds, and shoots lightning for it's animation and is on a 12 second cooldown. I know this isn't a "stun" but could be confused as one by some due to the animation, so I've added it here.
Or Force Lightning, which isn't a "stun" at all but rather works like a channeled Force Slow doing consistent damage?
Just curious, that's all, as "Lightning Stun" is very vague.