How to get internship after freshman year?

I will be attending Notre Dame this upcoming fall, and have already connected with some analysts/associates/VPs at Blackstone, BlackRock, and Goldman. I will most likely double major in Econ and Poli Sci while still taking finance, accounting classes.

However, when during my freshman year should I contact these people again to I guess remind them that I exist and am interested in pursuing a career and internship at their respective firms? Also, how should I ask them for an internship in the summer after my freshman year?

• I realize that there is not much a freshman intern can do, so if interning at these large firms end up not being possible, I will try to get an internship at a boutique bank.