Linda, Peace lilys can take a good deal of light & even direct sun but they can get heat stress such as sitting in a hot car. Also, being that it came form a florist I likely was greehouse raised in low light and has continued it's low light journey. It will do as the photos indicate if it's exposed to too much light too fast. You will need to gradually allow it more & more light. They can be sunburned even in the house if exposed to too much sun too soon. Be cautious of overwatering also. As woofie says, re-potting is a good idea.
I will tell you too from my persoanl experiences with them that it is normal for the older leaves to do that when the plant is going through a renewal cycle. Cut those leaves off; it won't hurt the plant.
Honestly, it looks very much to me like it got sunburned sitting in the hot car with the sun shining through the window.
