SQL join: where clause vs. on clause

SELECT *
FROM Orders
LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID
WHERE Orders.ID = 12345
and

SELECT *
FROM Orders
LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID
    AND Orders.ID = 12345


a. WHERE clause: After joining. Records will be filtered after join has taken place.

b. ON clause - Before joining. Records (from right table) will be filtered before joining