Life / Need Help Finding a Specific Polish Novel [9]

My wife, who is Polish, frequently mentions a book she used to read every Summer when she visited relatives. She remembers very little about the book, only that she loved it.

I would very much like to find this book for her, but I have had little success.

Here is what I know (or at least, what she thinks she can remember):
- the book was in Polish, but that does not mean it was originally a Polish novel
- she believes one of the main characters was named "Lenka" (or close to this)
- the plot had a romantic element, although it may not have been an actual romance novel
- it would have been published before the late-1980's

I know that is not much to go on, but if this jogs something in anyone's mind, I would really appreciate the help.

Some additional information:

- it might be set in the Ukraine back when it was part of Poland
- it might set in Lwow or Litwa

Thanks again for the help.