Can I play an Origin downloaded game offline?

Hi guys,

I'm relatively new to all of this, so here goes.

I downloaded C&C Generals and Zero Hour from Origin recently. Is it in any way possible to play this game offline?

I figured that since I downloaded the entire game, it is installed on my computer, so whether I am online or offline shouldn't be an issue, yet whenever I try to run it, the Origin login screen appears rather than the game launcher.

Any help would be much appreciated.

Thanks,