I spoke with my mother and she never heard of Bert or Lottie Elwood. Do not be discouraged though, you would not believe some of the things I have encountered in my search for my ancestors. The most basic step in doing geneology is making sure that you send for all of the birth and death certificates that you can. One thing to your advantage is that you have Bert's place and date of birth thats all you need!
In the State of Pennsylvania you can acquire both birth and death certificates of your ancestors if they were born or died after 1900. I think it costs $4.00 for a birth or death certificate, but don't take my word on that. All you have to do is a search on any search engine for PA Vital Statistics and you will be provided with all the info you need. By the way, only you can request records of your ancestors. I recommend both a birth and death certificate. That way you can get all the available information. Since Bert was born in Avonmore around the turn of the century I am reasonably sure he will prove to be one of our cousins. Let me know what you find out, OK?