Never lightning??!! The Front Range here has lightning - and lots of it- almost every afternoon in the summer. Normally there is a thunderstorm for a couple hours. That's why they tell hikers to be off the mountain by noon. There's a nice lightning storm going on right now as I look out my window.
Lived in Denver for nearly a decade, starting late May early June each year thunderstorms were prevalent most afternoons. This mini monsoon season went on well into July before dissipating. Has to do with the warm air over the plains pushing against the front range, rising into the colder air aloft and voila ... clouds form into thunderheads dropping mostly rain, occasionally hail. The individual who responded earlier that lightening never occurs in Colorado obviously is clueless.