Lag is caused by the amount of particles that are generated by Orbital strike. on SKyline it generates a lot more of particles because Skyline is a big hight map.
So the fix is - lower the level, and swap the "real" hight for a texture.
I must be the only one who does not LAG in an orbital strike?
Its a fault with the game so yes, you will lag also. Orbital Strike lag makes it appear as if everyone but you is lagging. You are free to move around but to everyone else you will be standing still as they will be standing still from your perspective.