I am getting the same error. It seems to of started when the site did an automatic update on Saturday morning 06.05.16. I presume it was Storefront being updated.
Did you find a way to fix it?
This was my error message:
Parse error: syntax error, unexpected T_FUNCTION in /home4/mysite/public_html/wp-content/themes/storefront/inc/customizer/class-storefront-customizer.php on line 73
many thanks
Votion