Are you allowed in this situation to drive onto the lane on the left?

There are yellow road markings on the roadway, which means a temporary traffic arrangement during roadworks. In the lane on the left a large yellow lane-change arrow is painted, pointing to the right - it orders drivers in that lane to move into your lane, because the left lane ends. The yellow line between the lanes is broken, so it is not the line that prohibits entry - it is prohibited by the meaning of the arrow: you do not drive into a lane that the markings are telling drivers to leave.

When there are both white and yellow markings on the road showing different behaviour, the yellow ones apply. A lane-change arrow means an order to move into the adjacent lane shown by the arrow; the only drivers it does not apply to are those for whom the further section of that lane is intended. So you stay in your lane and leave room for vehicles moving from the left lane into yours.

Legal basis: § 85 para. 3 and § 87 para. 3 of the Regulation on road signs and signals