According to this link you can set a local policy for this or reg key:
Open secpol.msc and navigate to Local Policies, Security Options and then find Interactive Logon: Do not display last user name and set it to Disabled
Open regedit and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System and change the DWORD value of the key dontdisplaylastusername to 1
Option 1 worked for me at least.