Arturia Officially supports El Capitan. Quote from the email sent to users; "Dear musician, Our virtual instruments are now compatible with Apple’s latest operating system, Mac OS X 10.11, El Capitan. The patches are included in the recent updates of our software and Mac OS X. We invite you to update your Arturia software using the Arturia Software Center. If you were waiting for it, you can now update your Mac computer with no risk of disturbance. Thank you for your patience."
Keep up with compatibility here.