Complex sentence: The rivalry will take a one-year break in 2011, when Boise State leaves the WAC for the MWC, before resuming in 2012 when Hawaii joins the MWC for football.
Split into simpler sentences: The rivalry will take a one-year break in 2011, when Boise State leaves the WAC for the MWC. It will then resume for one year in 2012 when Hawaii joins the MWC for football.