First I'd like to recommend David Zabecki's "The German 1918 Offensives", which examines this option and the historic outcomes of the battles. It also has tremendously useful maps that you won't find online for this POD.
Now as to this specific question, you'd have to be more specific on the POD. The operation was a major success as it was, but it was the first in a series of offensives, rather than a war-winner by itself. However, if Ludendorff had stuck to his plan and not reinforced failures, costing lots of irreplaceable troops, moving on instead to other operations in sequence, things could have been much different.
http://en.wikipedia.org/wiki/Operation_Michael
Instead of going after Arras, which was an unnecessary bloodletting, and letting the offensive run its course, Ludendorff could then shift his reinforcements north to run Operation George, instead of losing so many men and being forced to run Georgette, the scaled down version of the plan.
http://en.wikipedia.org/wiki/Battle_of_the_Lys_(1918)
This battle is then much more likely to succeed, having more forces attacking at more points, while the Allied forces have been drawn to Amiens in response to Michael (again as planned). Launched in late March/very early April instead, this operation is much more likely to succeed in taking something(s) vital, like Hazebrouck, Ypres, Poperinghe.
This would provoke the collapse of the very shallow and vulnerable British supply network in Flanders, causing them to pull back to the coast, or risk their troops falling out of supply. While not forcing the Brits to abandon Northern France, or all of Belgium, it would be a major blow to morale and a boost to German ambitions. Now from here, more shots at the British would be necessary and desirable, as they would have had most of their trench lines, which took years to develop, forcibly removed from their control. The British were vulnerable, and if the right steps were taken, they could be driven out of Northern France.
Combine this with a reasonable peace offer, which Ludendorff was supposedly trying to work on, and an armistice perhaps could have been negotiated (assuming the French/British civilian government were convinced that the Germans had hurt them too much and their offer was the best deal). That is still unlikely. The Belgians would have to cut a deal and drop out of the war, again unlikely. From this point the Germans would have to offer a lot of concessions, which they were not likely to do.
The only way to get the French out of the war, the only way to peace at this point, would be to drive the British from the continent and focus on the French. But in driving the British out, which would require excellent luck and skill the German high command did not possess, would probably exhaust German resources, and the British would be back.
I really don't see a good end to the war for the Germans, though with a more success series of offensives, they might not get as raw of a deal if they leverage their position properly (though given German diplomatic records, this is nigh impossible).