Proxmox KVM virtual machine: Cannot delete due to missing storage

Today we encountered a situation where a Proxmox system’s KVM virtual machine refused to delete after the storage volume that it’s virtual HDD resided on was lost; trying to delete the KVM from the web GUI resulted in the following error:  
TASK ERROR: storage ‘proxmoxHDD’ does not exists
  Attempting to delete it from the command line using:  
qm destroy [VM ID]
  …resulted in:  
storage ‘proxmoxHDD’ does not exists
  Fortunately, there’s a way around this. The KVM config files live in:  
/etc/pve/qemu-server
  Move or erase the [VM ID].conf file and when you refresh your web GUI the VM should be gone.