Blue smoke cloud when starting

[DonM]

I have a 2003 Toyota Camry four cylinder SE which I have personally serviced myself from purchase until recently. During this time, I have changed the oil, using a premium petroleum based oil, and the oil filter, using a Toyota filter, every three thousand miles or less. I now have just over 65,000 miles on the car and have had no engine problems or a need to add oil. In December, I decided that I could no longer do this work because of my age. So, I had an oil and filter change done by the Toyota dealer I purchase my cars from. When I returned home after this work, I checked the oil level and found that they had put at least one quart too much oil in. I returned to the dealer who drained it down to the proper level. After a few weeks, I started noticing a large puff of blue smoke when I started the engine; if the car hadn't been started for a few days, it was clouds of blue smoke; this always stopped after a few seconds. Thinking that if the Toyota person didn't know the proper amount of oil, he might also have installed synthetic oil instead of regular oil. So, after a few weeks, once more I got under the car and changed the oil and filter as before; it didn't make any difference; still lots of blue smoke on startup. Everything I read says the problem I am now experiencing is leaking valve guides/seals. Is it possible that the dealer installed synthetic motor oil and the few weeks I ran with synthetic oil, after thirteen years of regular oil, could have damaged the valve guides/seals?