It isn't too important to get a certain model of helmet, shoulders, or elbows. Just go to a local sporting goods store and get what fits well. Your team may supply helmets, which would make life easier. For playing attack or mid you're going to want something without too much bulk, but solid enough that you'll be able to take some slashes.
Gloves and stick are by far the most important (obviously), and vary the most for personal preference. Throughout high school, I used a Warrior titanium shaft, and these heads: Proton Power, Evo Pro, Revo Pro, Stiffy, Razor Pro, E3, and a Gait that I don't remember the name of. My favorite was probably the Revo Pro or the Razor Pro. When you buy a head, you should expect to spend at least $85. I would recommend just browsing through lacrosse.com... Most heads will have a recommended position in the info.
And gloves... I always loved Mac Daddys. And I found that Brine usually runs small (just something to keep in mind).
Good luck man, and enjoy! I also haven't played in a few years, but hopefully I'm not too out of the loop with equipment.
Buy sick clothes, get 20% off with rep code FLM