With Azure Active Directory Connect installed the following commands will come in handy when you need to check sync settings, force a sync or pause/un-pause synchronization.

# Checking sync settings
# Forcing a sync
Start-ADSyncSyncCycle Initial
Start-ADSyncSyncCycle Delta

# Synchronization can be paused or un-paused with the following PowerShell cmdlets.
Set-ADSyncScheduler –SyncCycleEnabled $False
Set-ADSyncScheduler –SyncCycleEnabled $True