Ok, I'm going to give this fellow a... more kind, answer.
No, elites will not be in multiplayer matchmaking. However, it is still unknown and possible that they will be in custom games and forge. Also, the idea of Elite Ops is still floating around as a substitution for their absence. They will also, as you know, be a secondary antagonist in the campaign.
They are not playable in multiplayer because of the tie with campaign. Multiplayer in halo 4 is simulated spartan combat training aboard the Infinity. This means, the Spartan IV's in training, 'train' against each other. Why, do you ask, don't they fight elites if it is training for combat with them? Because with going up against each other, as opposed to programmed elites, is a much more realistic environment. They learn each others tactics, how they fight, and what they do in a combat situation. This is impossible to determine facing a programmed elite. Hence the "Artificial" In "Artificial Intelligence". Fighting an opponent that can think in a situation, and make a real decision, is a much better exercise than that of a program.
I do hope my answer helped. I know, it is long, but I just wanted to explain thoroughly.