There should be no major loss of condition from a month off training if you have been training consistently for the past year. The key is to maintain a sensible level of nutrition so your body doesn't go catabolising your muscles for protein.
Also, a trick I have learned with so many interruptions over the years, is to overtrain everything like a M.F. in the week before your lay-off. Your body will take at least week to recover from being belted and then your month off is really only three weeks off.
Oh, and it is nonsense using study as an excuse to not train. I was at my strongest in the year I got married, had our first child and was finishing off my MBA whilst still gainfully employed. Time management and prioritising what matters.