bwtr ,

 Ahh its easy make a lightning bolt or fire  , whatever effect you want in your photo software. Transparent background. I actually in this one made the layer huge 1200X1200 with the small sprite in the center. Than just use a plane in carrara load the png as texture map. Plug it into glow channel too. I like to use a subtract mixer and in channel 2 a value. you can adjust the glow it seems better than with multiply or add mixers. I scale the plane huge to so its out of the production window this prevents edge artifacts. face it to camera and adjust its depth to meet your scene. That is,  the plane is actually in the cloud not in front of it . This just really blends into the render so well you dont need postwork and the glow adds into the render. And of course you could use animated sprites something that you would need like after effects to do otherwise. you can also make lightnig shaped polygons like in the leaf tuts on the net :)  just trace the png with the poly tool.

Why pre work over postwork? To me its more predictable repeatable and reliable.