Find the current, or create a new command prompt shortcut. I did a right click on the Command prompt icon in start menu, and clicked find location.
Right click the shortcut, and click properties.
Change the target folder. It should have %windir%\system32\cmd.exe or something like it, in there already. 
Add a space and /k another space, and then your desired start location in "" eg. %windir%\system32\cmd.exe /k "cd C:\somepath\here"