Seeking WWI military records/info for grandfather, Lajos Hart or Harth, born about 1895 in or near Tiszanagyfalu, Hungary and reportely served in WWI. He was reportedly captured by Russian soldiers in Poland, and when the war ended he had to make his own way back to Hungary (so may have been listed as missing, captured or some other category).

I'm not clear where this info might be available. Any help would be MUCH appreciated.

Thank you!