I discovered the reason why I was not getting entries into my php_errors.log file related to permissions. Right now, I have set it to 666 (rw-rw-rw-) but surely this is a security weakness? Thus, my question.
php.ini file: error_log /var/log/httpd/php_errors.log log_errors On
# ls -ld /var/log /var/log/httpd /var/log/httpd/php_errors.log drwxr-xr-x 6 root root 4096 Jun 21 03:32 /var/log drwxr-xr-x 2 ec2-user ec2-user 4096 Jun 22 10:16 /var/log/httpd -rw-rw-rw- 1 ec2-user ec2-user 63 Jun 22 10:33 /var/log/httpd/php_errors.log
(Many thanks in advance)