Depending on your current theme, the title may be found in the `node.tpl.php`, the `page.tpl.php` (usually this one) or `html.tpl.php`. Enable theme debugging to toggle theme debug comments. That way, you see which templates control which portions of the page.

Add the following to `settings.php` and refresh a couple of times (clear cache if it becomes stubborn). Then inspect the page.

    $conf['theme_debug'] = true;

With theme debugging on, you'll also see the progression of template name suggestions in the comments, with the top most/most specific/longest name being selected first. 

You can also add to this list by altering the `theme_hook_suggestions` property in the variables argument of the appropriate `hook_preprocess_` hook. If I remember correctly, there's no suggestion content type suggestion for templates. If so, you'll have to add one.