@royho – Disregard.
@zubairmirza – I was able to figure it out; the form-checkout.php file needs to be updated. I did this by downloading a copy of /wp-content/themes/<theme>/woocommerce/checkout/form-checkout.php and /wp-content/plugins/woocommerce/templates/checkout/form-checkout.php. Then I used WinMerge to manually reconcile the differences.
@royho – I too am having trouble using Stripe checkout with the lambda theme. I realize you can’t troubleshoot a third-party theme, so I won’t ask you to do that. Instead, I was wondering if you have general advice of how to troubleshoot a theme that doesn’t work with the plugin? For example, are there certain common points of failure, or input fields that need to be named a certain way? Any guidance you could offer would be helpful.