If you're going to do it on a per-page basis, you'll have to use the page id. This is found in the id attribute on the page's body tag. In the case of your 'Who We Are' page it'd be "#collection-509c3dd7e4b0b5d93ca20b69 #top"
If you're going to do this consistently, take out the CSS and check the 'Options>Hide Page Title' tweak in the style editor. That will disable the title on all pages.
Using the CSS editor:
.homepage #top { display: none; }
Also check through the style tweaks, your template author may have provided an option for the homepage to not display a title.