The Bleeping Computer database description of the process "cvhsvc.exe" (https://www.bleepingcomputer.com/startups/Client_Virtualization_Handler-27218.html) correctly identifies it as part of the Office 2010 Click-to-Run Virtualization Handler. However, it describes it as being responsible for updating the Click-to-Run software.
The thing to keep in mind is that Office 2010 Click-to-Run was strongly based on App-V (Application Virtualization) technology and installs the Office software in a virtualized environment. The Office 2013 Click-to-Run departed a little more from App-V by not isolating the Office software in this manner.
It appears that "cvhsvc", "cvh.exe", and "officevirt.exe" - all components of the Virtualization Handler - were what enabled the virtualized software to "reach out" of its "bubble" into the normal disk addressing space to read and write user data. This Microsoft Answers forum thread (https://answers.microsoft.com/en-us/msoffice/forum/msoffice_install-mso_other-mso_2010/office-2010-doesnt-close-completely/adca530d-ad08-4c64-9874-f52ede05296b?messageId=0797a063-b1cd-4177-90c8-8176ea5def1e (02/24/201) provides evidence that "officevirt.exe" starts when a user data file is opened by any virtualized Office 2010 app.