It is racing's greatest dichotomy. Labelled by the official ParisLongchamp website as "la meilleure course au monde", the G1 Qatar Prix de l'Arc de Triomphe will have few who brook any argument with that claim. Yet it is the time of year within which it is framed that delivers the ultimate snag, with autumn's entry prompting an often drastic change in terrain and a late turnpike for the kings and queens of summer just past. Half of the previous 10 renewals of France's great monument have been run on testing...