Yep, as long as there's an attack roll, he's within 30', and the victim is flat-footed, it's all good.
Hi everybody: a(very creative) player of my group plays the role of a halfling Wizard(Invoker) - Rogue.
If he's well hidden, and the enemies are unaware of his presence, could he attempt a rogue sneak attack casting a ranged touch spell, such as Acid Splash, cast within the proper range for a sneak attack with a missile weapon? Is there any clear rule about this?
Many thanks!
Yup. it works.
The damage is the same type as the spell.
If the spell does ability score damage or level drain i think the sneak attack damage becomes negative energy damage. (this was how 3.5 worked, and I'm not aware of any changes in pathfinder)
You should have the player look at the arcane trickster prestige class.