They will probably decide that well after the game is completed

difficult to tell, i am guessing its going to be just after skyward sword, but then again there are strange machine monsters and the arrow that link used looked a bit technological, then again could have been maic or something

genuine question, who cares?

Not Nintendo that's for sure

defeated timeline or maybe even its a new timeline. my bet is a new timeline

Just before the Wand of Gamelon

Reply of The Year. 

Probably the most compelling evidence for a connection in what we've seen so far. Unclear exactly what it means, though. At a glance it would seem to suggest the game taking place between Ocarina and Twilight Princess, since we visit Lake Hylia in the former and there is no such bridge there, indicating it must have been built between the two games. But the overworld we've seen doesn't resemble the land of Hyrule in either of those games in the slightest. Sure, major landmarks are in similar locations, but that's pretty normal for Zelda games. The landscape and the state of the world are completely different from what we see in Ocarina and TP.

There are three other possibilities:

• The bridge was built before Ocarina of Time took place, and simply wasn't in the game. Basically, a retcon.
• The bridge was renovated after the events of Twilight Princess.
• A very similar-looking bridge happened to be built over Lake Hylia at time on any timeline.

Additionally, there's always the standard possibility that EAD3 didn't really think this through and just like that bridge design.