How to set redirect from upper case to lower case only for pseudo directories?

Question

Apache HTTP Server

I use the solution (the very first option)

https://ru.stackoverflow.com/questions/425398/%D0%A0%D0%B5%D0%B4%D0%B8%D1%80%D0%B5%D0%BA%D1%82-url-%D0%BD%D0%B0-%D0%BD%D0%B8%D0%B6%D0%BD%D0%B8%D0%B9-%D1%80%D0%B5%D0%B3%D0%B8%D1%81%D1%82%D1%80

My .htaccess:

Options -Indexes 
ErrorDocument 404 /404.php

<IfModule mod_php5.c>
  php_flag allow_call_time_pass_reference 1
  php_flag session.use_trans_sid off

  #php_value display_errors 1

  #php_value mbstring.internal_encoding UTF-8
</IfModule>

<IfModule mod_rewrite.c>
  Options +FollowSymLinks
  RewriteEngine On

  RewriteBase / 
  RewriteCond %{REQUEST_URI} ^[^A-Z]*[A-Z].*
  RewriteRule ^ ${lc:%{REQUEST_URI}} [L,R=301]

  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-l
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !/bitrix/urlrewrite.php$
  RewriteRule ^(.*)$ /bitrix/urlrewrite.php [L]
  RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization}]
</IfModule>

<IfModule mod_dir.c>
  DirectoryIndex index.php index.html
</IfModule>

<IfModule mod_expires.c>
  ExpiresActive on
  ExpiresByType image/jpeg "access plus 3 day"
  ExpiresByType image/gif "access plus 3 day"
</IfModule>

The solution works, but redirects all URLs.
Question: how to make it so that if a directory (file) of the form /CapsLoc/, CapsLoc.jpg, CapsLoc.css, CapsLoc.php, etc. physically exists, the redirect rule was not applied. But if this directory / file is not physically on the disk, then the rule with 301 redirects from upper to lower case was applied.