According to German newspaper "Express" (and subsequently several other sources citing them) after having made first contact last spring, Arsenal have had a bid of €23m for Lars Bender rejected by Bayer Leverkusen.

The following excerpt from the Guardian basically says as much as well.

"Arsenal's attempt to strengthen their midfield have been frustrated afterBayer Leverkusen knocked back an approach for the Germany international Lars Bender. The club have, however, signed the French French youth international striker Yaya Sanogo as a free agent after leaving Ligue 2 team Auxerre.

The Gunners had hoped to secure the 24-year-old, whose twin brother Sven plays at Borussia Dortmund, for about €23m (£18.5m) but the Bundesliga club quickly turned down the inquiry and have since made it clear Bender is not for sale at any price. Leverkusen sold André Schürrle to Chelsea and Dani Carvajal to Real Madrid earlier in the summer and are not under financial pressure to move on more of their first-team squad.

That represents a blow for Arsène Wenger, whose transfer policy this close season has always been geared towards strengthening the spine of his side with a striker, a central midfielder and an experienced goalkeeper his priorities."
Source: http://www.guardian.co.uk/football/2013/jul/01/arsenal-lars-bender-bayer-leverkusen

@foota
2nd kind of cdm, physical, tecnical, left right foot,one of the most complete CDM in the world and a key player for Benfica.
40m is an impossible fee since cardozo worth 15m this year. he is 24yo i think 25M is a good price.
@expertfoot
Dortmund players are going nowhere, they won't sell any of them.