Here is one idea. The Sprite code is at lines 162-175.
The sprites seem to stay fairly aligned with the LensFlare objects - at least vertically.
I may need to figure out how to make them align better horizontally.
I also need to figure out how to turn them off. I tried comparing the lat/lon of the sun with the camera.rotation. But I think the camera.rotation is in quaternions, not eulers.