Zero crossing detection circuit correct?
The zero crossing circuit you've designed is conceptually correct: however, it is not properly dimensioned. Precisely, the \$30\mathrm{k}\Omega\$ resistors that you removed from the original circuit not only have the function reduce the voltage going to the \$T_5\$ optocoupler (4N25 type) to a non destructive level, but also limit its input anode current \$I_A\$. Without them, the input photodiode of \$T_5\$ is likely to be destroyed at power-up. Therefore you should add two other resistors in series to the secondary winding of the transformer, in order to limit the maximum value of \$I_A\$.

Edit. Even if the problem seem likely to be solved by setting properly the pin of the Arduino board, the OP has asked advice on how to properly dimensioning the input resistor of the optocoupler, so I decided to add the following notes. Let's start by considering the following BJT-output optocoupler standard circuit:







simulate this circuit &ndash; Schematic created using CircuitLab

where \$R_C\$ is the output collector (pull-up) resistor and \$R_{in}\$ is the input bias resistor.


How to properly design the input resistor \$R_{in}\$? Assuming that the maximum collector current of \$Q_1\$ is 
$$
I_{C1_\max}=\frac{V_{CC}}{R_C}
$$
we must assure that the anode current of \$D_1\$ is sufficient to produce such collector photocurrent under every condition. This is accomplished by considering the minimum peak voltage \$V_{in}\$, the maximum anode voltage of \$D_1\$ and the minimum guaranteed CTR (\$\equiv\$current transfer ratio), i.e. we should require that
$$
R_{in}\le \mathrm{CTR}\frac{V_{inpk_{\min}}-V_{A_\max}}{I_{C1_\max}}
$$
This assures that the \$Q_1\$ goes in saturation. At the same time we need that the anode current does not rise above its absolute maximum rating, therefore we should require that 
$$
I_{A_\max}\gg \frac{V_{inpk_{\max}}-V_{A_\min}}{R_{in}}\iff R_{in}\gg \frac{V_{inpk_{\max}}-V_{A_\min}}{I_{A_\max}}
$$
In sum,
$$
 \frac{V_{inpk_{\max}}-V_{A_\min}}{I_{A_\max}} \ll R_{in} \le \mathrm{CTR}\frac{V_{inpk_{\min}}-V_{A_\max}}{I_{C1_\max}}
$$
Considerations on the rise/fall time of the collector voltage of \$Q_1\$. Optocouplers are not exactly the fastes devices available on the market, due to inherent accumulation in their B-C region of optically generated minority carries, which are not quickly removable, and their slow generation. However, the Turn On-transient is usually faster since it doesn't involves the removal of stored charges, thus if you need "steep", well  defined edges as your input signals, choose the \$V_{CE_{Q_1}}\$ falling ones.