I need help with understanding elemental storm

[sheepstar85]

So I know what it does and how it does it with the critical hits, but when I'm in the passive skill tree and hold shift it says there are no skills affected. However I'm using a lightning bolt staff, spark and arc spells and they all do critical damage, so I don't understand why elemental storm isn't working.

Also if only certain spells work with it, then how do I know what ones work, so I can get them and use them.