Is it possible to use the node package gulp-livereload to refresh the page on just a change, without pressing command+s to save the file you are editing?
Currently it is not possible (not only gulp-livereload, but all livereload plugins). From the official site:
LiveReload monitors changes in the file system. As soon as you save a file, it is preprocessed as needed, and the browser is refreshed.
However, there is a plugin for Sublime Text and Chrome that offers CSS live editing, Emmet Livestyle