what is causing oil to burn?

What is your question?

the common response is the valve guides, a known problem. However, it does not burn upon starting, even when revved, it does not burn when accelerating, even when really pushing it. It will, start burning when the engine is warm and when it has been idling for at least 3 minutes. Then, big plume of blue smoke, which goes away after accelerating. And yes, the car has 101,000 miles. Oh, just got the oil changed and only added a half a quart between changes....about 8000 miles. Any ideas?