Great! Placing it in the Additional CSS field didn’t work, but since I had a child theme active already for this purpose, putting it directly in the CSS file did work with a slight modification because the font size wasn’t passing through.
Final code for anyone else who may need it:
.blog h1.page-title {
font-size:0;
}
.blog h1.page-title:before {
content: "Articles/Events";
font-size:28px !important;
}