inserting em-dash at beginning of paragraph
 

I'm struggling trying to add an em-dash to the beginning of every paragraph in my document with a certain style ("dialogue"). I've tried to search for the style (no problem) and replace with ^+^& but that adds an emdash to the start of the following paragraph. It seems to find the paragraph marker with "dialogue" style and then replace forward. How can I get it to work with the text that comes in front of the paragraph marker (say, replace alltext with emdash+alltext)?

I can't have bullets (for instance, em-dashes as bullets) in the document.

This is a document with nearly 2000 paragraphs of dialogue interspersed with other styles, so I really need an automated solution!
Thanks!