Site found by a Google search on
lettuce bolt
http://dede.essortment.com/lettucediseases_ring.htm
Quote from that site
"Usually bolting in lettuce plants is the result of exposure to exceedingly cold temperatures early on in the plant's growth, even though bolting doesnt actually occur until the warmer temperatures begin."
isn't a bolting lettuce just doing what comes naturally and just flower to produce seeds. try staggering your planting or eat more lettuce more quickly. or get a rabbit