[Once Leo's noticed that there are a lot more people around, he's going to be keeping an eye and looking. He hopes to see his family, of course, so he's mostly looking for them instead of helping with the tents and all the work there is to do.
It doesn't take him very long to see that Arthur is there too and he approaches without really thinking about it. He does stop though before talking because he has no idea if you remember he isn't Merlin, and he hasn't seen him around yet.]