Is a VOR usable on the ground when it's located at a higher elevation than the receiver?
In order to receive a VOR station there must be a line of sight from the airplane to the VOR.  This is basically what your chart is referencing, you can maintain line of sight at longer distances at higher altitudes.  It could be possible that the VOR is higher than the airplane and you could receive the VOR while flying below the VOR as long as you have line of sight.  However it would probably be best to make sure you have enough altitude before you try to intercept the VOR to make sure you don't have a controlled flight into terrain incident.