the_permalink displays post ID URL for future posts

I use a WP template to generate an email newsletter. I display future posts and until recently using the_permalink and get_permalink displayed the full human-readable URL (e.g. /this-is-a-page). Now it displays the post ID URL (e.g. ?p=5800). How do I get WP to display the human-readable URL?

More strange, perhaps, on the Add/Edit page for my future entries, when I add or update a story to be published in the future, the message up top “Post updated. View post” link goes to the post ID URL. However, the View Post button to the right of the Permalink, located directly under the entry title input field, goes to the human-readable URL.

I’ve gone into wp-admin/includes/post.php to investigate the difference between the View Post button and View Post link with nothing obvious jumping out at me. get_permalink also doesn’t take a parameter to force non post ID links.

It’s a major PITA and totally counter-productive to manually convert the post URLs to human readable URLs. I need the HTML output from my template to set up HTML emails before the stories are published.

Any ideas how to retrieve and display human-readable URLs for future stories?

Thanks for any help and insights.