I have a Cold / Lightning sorc, and she works wonderfully also in solo Hell games, with her good Act2 defiance tank / merc.
My skills / stats project:
1 Warmth
1 Ice bolt
1 Frozen armor
1 Ice blast
1 Glacial spike
1 Frost nova
1 Blizzard
20 Frozen orb
1 Cold mastery
1 Shiver armor (your armor)
1 Static field
1 Charged bolt
1 Telekinesis
1 Teleport
20 Lightning
20 Chain Lightning
20 Lightning mastery
all the remaining points should go to Charged bolt or Nova (synergies 4 Lightning and Chain lightning, your main attack spells)
Strength enough to wear gear
Dexterity base or 75 if you want to use Wizardspike
Energy base or some points, but only if you have no SoJs / Frostburn / Lidless / Mana sc's, which are usually sufficient to make you have a decent amount of mana at higher levels.
Equipment... depends on what you have.