I think this is not possible, but I'm not sure
Is there any way to see my enemy summoner name BEFORE loading screen?
viki69 (05-04-2015)
Yes it actually is possible you just have to use a method to pull the summoner details of both teams except of just one(I already made one in my java client but definitely won't release that yet since its crap right now).
LOLNOTES used to do this ,but no longer is updated and even if so, it is easily detectable.