I'm currently taking a Bio course with a professor that I'm forming a great relationship with and I think I'd like to ask him to write me a LOR. Only thing is I won't be applying to D-schools until next cycle. Can I ask him to write me one this summer? Or should I wait until the Spring? And if I do ask him to write me one this summer, where is the letter kept until it's time for applications to open up next cycle?