Assuming you're pressing Enter at the end of each line, so each line
is a separate paragraph:
Define two paragraph styles, one for each font.* In the definition of
each style, specify the other style as the "style for following
paragraph".
*In case you don't know, to define a style, click Format > Styles and
Formatting (Word 2003 and earlier) or press Ctrl+Alt+Shift+S (Word
2007) to open the Styles pane, then click the New Style button.
--
Regards,
Jay Freedman
Microsoft Word MVP
Email cannot be acknowledged; please post all follow-ups to the
newsgroup so all may benefit.