Hi.
In the post/thread linked below, although the question was about indents, the answer is pretty much the same.
Except that in your case you want to make sure the style used is “save all formatting” if your lines are paragraphs of their own, or a “character attributes” style, if rather part of a paragraph of your other font. (If you ain’t sure, use a character attributes style.)
(In short the answer to your question is : use a style.)