Hi Jai,
When my DS was 6, he started at a new school in 1st grade. While he does not have allergies, he hated the smell of peanut butter so he sat at the peanut free table at lunch and made a couple of friends, one of whom invited him to a birthday party. He met some other kids there and then I just worked hard to keep those kids in a play date circle. Eventually this group developed into the scout troop. Fast forward to the 4th grade when I transferred him to an all gifted track school and he had to start from scratch. He would mention a few names of kids he had met and I would arrange play dates with them and keep doing that. I fully admit it took a lot of work on my end but the upshot was I became good friends with the parents of those kids and even though some have spread out to other middle schools now, we keep the kids in touch. He's met new friends in middle school now and I try to get to know the parents of new kids he meets. The kids tend to be like him, too, so we parents understood each other. So here we are in 7th grade and he does not have a bunch of really close friends but he has a little group of maybe 2-3 friends sometimes 4-5 who he hangs out with at lunch.
That's a long way of saying that it took some work. Sometimes the play dates I arranged were not reciprocated but I kept working at it until he found kids who were sort of like him and they generally "stuck".
Good luck!