The 'soft line endings' cannot be found with regular Find/Change, but you can access lines through Javascript.
But doing this with a Javascript for this is extremely tricky — it changes the line ending, and that could imply that a previously untouched occurrence would need to be changed as well (and that in turn may influence yet other line breaks, or — because InDesign has a very advanced "complete paragraph" based composition engine — even the one line that caused this particular change …)
I'd use a GREP style for this. Make a character style that only applies "No Break", and have it applied to this GREP string:
\w/\w