Why does a 1995 Cadillac Concourse have a popping noise in the front end when making turns to left or right?

The Cv joint in the front axle has worn out and needs to be replaced. Most of the time it is cheaper to replace the whole axle than to rebuild just the joint itself. I would suggest that you investigate the bearing(s) at the top of the strut tower. If the popping occurs when you turn the steering wheel, then it is this bearing not the CV joint... the CV joint will make noise as the front wheels are turning. Your question seems to indicate the problem when turning the steering wheel. It could be one or both of the bearings on either side. Judging by the year, this could be the problem. It requires dropping the strut and replacement of the bearing then a wheel alignment for either one or both bearings.