When I read a foreign name, Jack, without having heard somebody say it first - such as a newsreader - I want to know how it's meant to be pronounced.
For instance, when I first read about the Bulgarian footballer Dirk Kuyt I wondered how to pronounce that: koyt? kite? kait? It turned out to be kowt, but I had to wait for a while before hearing a commentator say it.
If I were you, I'd write 'Eltsyn (pronounced Yeltsyn) . . .' (if I understood you correctly to mean that) the first time it appears.