Mapped network drives created by an elevated process will not be visible to an unelevated process and vice versa. This has been the case since Windows Vista. Since Explorer doesn't run elevated (unless you fully disable UAC), it doesn't see the drives you made with your administrative command prompt.
To disable that isolation, you can modify the Registry, as instructed by this TechNet article. Navigate to this key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System Create a DWORD entry named EnableLinkedConnections with a value of 1. Reboot the computer. Network drives mapped by the same user, even under different security contexts, will always appear to programs running as that user.